How to repeat a single frame?
In the original video's strip, there are two handles, one at each end. Simply pull the right side's end out with the mouse button. (Left button I think)
Beware of any faulty or black frames that might be present at the end.
These can be sliced off with SHIFT-K.  Delete those.
Once the very end frame is valid video pull the handle to the right and this will extend that last frame out for as many frames as you like. You can use this extension to fade the scene out to black by keyframing the strip's opacity.
Take some abience audio from another part, copy and lay that with the silent extension, fade that out over the same frames as your inserted fade to black.
You can copy/paste the original audio strip, into a free strip and if I remember rightly, you might also be able to duplicate it with SH-D and simply drag the copy up to a free strip.  Once the copy is established, it can be sliced up to extract whatever you want, lay it where it's needed.